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CONTROLLER
ELECTRONIC TEMPERATURE CONTROLS
The Geyser C-series comes standard with a Johnson
Controls A421 Model # A421GBF-x controller. This
control is used to control the water temperature in the
tank by supplying a call signal to the Heat Pump Water
Heater. The control comes with some factory settings.
The A421 control should never be set higher
than 150°F, failure to comply could void the
warranty.
Johnson Controls A421 Controller
Model # A421GBF-x
Notice:
Please make sure you are running a Johnson controller
(pictured above) before you continue to the next page. If you
are running a PLC (Programmable Logic Controller) skip to the
directions starting on page 38.
33.